Clinical Features of Acute Chikungunya Virus Infection in Children and Adults during an Outbreak in the Maldives

The chikungunya virus is an arthritogenic arbovirus that has re-emerged in many tropical and subtropical regions, causing explosive outbreaks. This re-emergence is due to a genomic polymorphism that has increased the vector susceptibility of the virus. The majority of those infected with chikungunya virus exhibit symptoms of fever, rash, and debilitating polyarthralgia or arthritis. Symptoms can persist for weeks, and patients can relapse months later. Fatalities are rare, but individuals of extreme age can develop severe infection. Here, we describe the 2019 outbreak, the second-largest since the virus re-emerged in the Maldives after the 2004 Indian Ocean epidemic, in which a total of 1,470 cases were reported to the Health Ministry. Sixty-seven patients presenting at the main referral tertiary care hospital in the Maldives capital with acute undifferentiated illness were recruited following a negative dengue serology. A novel point-of-care antigen kit was used to screen suspected cases, 50 of which were subsequently confirmed using real-time reverse transcription-polymerase chain reaction. We describe the genotype and polymorphism of Maldives chikungunya virus using phylogenetic analysis. All isolates were consistent with the East Central South African genotype of the Indian Ocean lineage, with a specific E1-K211E mutation. In addition, we explored the clinical and laboratory manifestations of acute chikungunya in children and adults, of which severe infection was found in some children, whereas arthritis primarily occurred in adults. Arthritides in adults occurred irrespective of underlying comorbidities and were associated with the degree of viremia.